FURUNO High-Speed Fairing Block for B744V / 525STID-MSD – AIR-033-476

Description

The FURUNO AIR-033-476 is a high-speed fairing block used with selected Airmar/Furuno through-hull transducers. A fairing block is not simply a spacer: it is cut to compensate for hull deadrise, keeps the transducer element aimed more nearly vertical and presents a streamlined shape to the water. On a faster boat, that combination can materially improve the quality of depth and fish-finder data by reducing turbulence and aeration around the transducer face.

• Deadrise correction: The block is cut to the hull angle so the transducer element can be oriented correctly relative to the waterline.
• Cleaner water flow: Streamlined profile helps reduce bubbles and turbulence reaching the acoustic face at speed.
• High-speed sonar support: Useful on installations where a bare stem or poorly aligned transducer would lose bottom lock as vessel speed increases.
• Model-specific fit: Intended for Airmar B744V / Furuno 525STID-MSD and related long-stem installations; fairing blocks that look similar are not automatically interchangeable.
• Service / replacement component: Appropriate when replacing a damaged fairing or moving a compatible transducer to a new hull.

Why Fairing Geometry Matters

A through-hull transducer that points sideways because of hull deadrise sends part of its acoustic beam away from the bottom. The fairing is shaped and cut so the sensor can sit in a more useful orientation. It also creates a smoother leading edge than a blunt housing, helping water remain attached to the hull and reducing acoustic noise from bubbles.

Installation Requires Hull-Specific Cutting

The installer normally measures deadrise at the actual transducer location and cuts the fairing to match. The upper portion acts as an interior backing block while the lower portion forms the external hydrodynamic fairing, depending on the transducer design. This is precision hull work: an incorrect cut can misalign the transducer or create a poor sealing surface.

Compatibility

Furuno lists AIR-033-476 as the high-speed fairing associated with the B744V-family 525STID-MSD/525STID-MSD7 style bronze multisensors. It is the appropriate reference when servicing those installations, subject to stem and hull-thickness requirements.

Always confirm the exact transducer model, stem diameter and fairing part number before haul-out. Ordering by appearance alone is risky because Airmar produces many related housings with different stems, inserts and fairing dimensions.

What’s in the Box

• AIR-033-476 high-speed fairing block

Specifications

• Product type: High-speed transducer fairing block
• Application: Through-hull transducer alignment and hydrodynamic fairing
• Compatible family: Airmar B744V / Furuno 525STID-MSD and related long-stem installations
• Installation: Cut to vessel deadrise and transducer location
• Important: Verify exact transducer/fairing match before hull machining